policy.h File Reference

#include "consensus/consensus.h"
#include "script/interpreter.h"
#include "script/standard.h"
#include <string>

Go to the source code of this file.

Functions
bool	IsStandard (const CScript &scriptPubKey, txnouttype &whichType)
bool	IsStandardTx (const CTransaction &tx, std::string &reason)
bool	AreInputsStandard (const CTransaction &tx, const CCoinsViewCache &mapInputs)

Variables
static const unsigned int	DEFAULT_BLOCK_MAX_SIZE = 750000
static const unsigned int	DEFAULT_BLOCK_MIN_SIZE = 0
static const unsigned int	DEFAULT_BLOCK_PRIORITY_SIZE = 10000
static const unsigned int	MAX_STANDARD_TX_SIZE = 100000
static const unsigned int	MAX_P2SH_SIGOPS = 15
static const unsigned int	MAX_STANDARD_TX_SIGOPS = 4000
static const unsigned int	DEFAULT_MAX_MEMPOOL_SIZE = 300
static const unsigned int	STANDARD_SCRIPT_VERIFY_FLAGS
static const unsigned int	STANDARD_NOT_MANDATORY_VERIFY_FLAGS = STANDARD_SCRIPT_VERIFY_FLAGS & ~MANDATORY_SCRIPT_VERIFY_FLAGS
static const unsigned int	STANDARD_LOCKTIME_VERIFY_FLAGS

Function Documentation

AreInputsStandard()

bool AreInputsStandard	(	const CTransaction &	tx,
		const CCoinsViewCache &	mapInputs
	)

Check for standard transaction types

Parameters

[in]

mapInputs

Map of previous transactions that have outputs we're spending

Returns

True if all inputs (scriptSigs) use only standard transaction forms

Definition at line 123 of file policy.cpp.

Referenced by AcceptToMemoryPoolWorker().

IsStandard()

bool IsStandard	(	const CScript &	scriptPubKey,
		txnouttype &	whichType
	)

Check transaction inputs to mitigate two potential denial-of-service attacks:

1. scriptSigs with extra data stuffed into them, not consumed by scriptPubKey (or P2SH script)
2. P2SH scripts with a crazy number of expensive CHECKSIG/CHECKMULTISIG operations

Check transaction inputs, and make sure any pay-to-script-hash transactions are evaluating IsStandard scripts

Why bother? To avoid denial-of-service attacks; an attacker can submit a standard HASH... OP_EQUAL transaction, which will get accepted into blocks. The redemption script can be anything; an attacker could use a very expensive-to-check-upon-redemption script like: DUP CHECKSIG DROP ... repeated 100 times... OP_1

Definition at line 37 of file policy.cpp.

Referenced by IsStandardTx().

IsStandardTx()

bool IsStandardTx	(	const CTransaction &	tx,
		std::string &	reason
	)

Check for standard transaction types

Returns

True if all outputs (scriptPubKeys) use only standard transaction forms

Definition at line 59 of file policy.cpp.

Referenced by AcceptToMemoryPoolWorker().

Variable Documentation

DEFAULT_BLOCK_MAX_SIZE

const unsigned int DEFAULT_BLOCK_MAX_SIZE = 750000

static

Default for -blockmaxsize and -blockminsize, which control the range of sizes the mining code will create

Definition at line 18 of file policy.h.

Referenced by CreateNewBlock(), and HelpMessage().

DEFAULT_BLOCK_MIN_SIZE

const unsigned int DEFAULT_BLOCK_MIN_SIZE = 0

static

Definition at line 19 of file policy.h.

Referenced by CreateNewBlock(), and HelpMessage().

DEFAULT_BLOCK_PRIORITY_SIZE

const unsigned int DEFAULT_BLOCK_PRIORITY_SIZE = 10000

static

Default for -blockprioritysize, maximum space for zero/low-fee transactions

Definition at line 21 of file policy.h.

Referenced by CreateNewBlock(), and HelpMessage().

DEFAULT_MAX_MEMPOOL_SIZE

const unsigned int DEFAULT_MAX_MEMPOOL_SIZE = 300

static

Default for -maxmempool, maximum megabytes of mempool memory usage

Definition at line 29 of file policy.h.

Referenced by AcceptToMemoryPoolWorker(), ActivateBestChainStep(), AppInit2(), CBlockPolicyEstimator::estimateSmartFee(), CBlockPolicyEstimator::estimateSmartPriority(), HelpMessage(), InvalidateBlock(), and mempoolInfoToJSON().

MAX_P2SH_SIGOPS

const unsigned int MAX_P2SH_SIGOPS = 15

static

Maximum number of signature check operations in an IsStandard() P2SH script

Definition at line 25 of file policy.h.

Referenced by AreInputsStandard().

MAX_STANDARD_TX_SIGOPS

const unsigned int MAX_STANDARD_TX_SIGOPS = 4000

static

The maximum number of sigops we're willing to relay/mine in a single tx

Definition at line 27 of file policy.h.

Referenced by AcceptToMemoryPoolWorker().

MAX_STANDARD_TX_SIZE

const unsigned int MAX_STANDARD_TX_SIZE = 100000

static

The maximum size for transactions we're willing to relay/mine

Definition at line 23 of file policy.h.

Referenced by ContextualCheckBlock(), ContextualCheckTransaction(), CWallet::CreateTransaction(), and IsStandardTx().

STANDARD_LOCKTIME_VERIFY_FLAGS

const unsigned int STANDARD_LOCKTIME_VERIFY_FLAGS

static

Initial value:

= LOCKTIME_VERIFY_SEQUENCE |
                                                           LOCKTIME_MEDIAN_TIME_PAST

Used as the flags parameter to sequence and nLocktime checks in non-consensus code.

Definition at line 50 of file policy.h.

Referenced by AcceptToMemoryPoolWorker(), ActivateBestChainStep(), CreateNewBlock(), and InvalidateBlock().

STANDARD_NOT_MANDATORY_VERIFY_FLAGS

const unsigned int STANDARD_NOT_MANDATORY_VERIFY_FLAGS = STANDARD_SCRIPT_VERIFY_FLAGS & ~MANDATORY_SCRIPT_VERIFY_FLAGS

static

For convenience, standard but not mandatory verify flags.

Definition at line 47 of file policy.h.

Referenced by CheckInputs().

STANDARD_SCRIPT_VERIFY_FLAGS

const unsigned int STANDARD_SCRIPT_VERIFY_FLAGS

static

Initial value:

= MANDATORY_SCRIPT_VERIFY_FLAGS |
                                                         SCRIPT_VERIFY_DERSIG |
                                                         SCRIPT_VERIFY_STRICTENC |
                                                         SCRIPT_VERIFY_MINIMALDATA |
                                                         SCRIPT_VERIFY_NULLDUMMY |
                                                         SCRIPT_VERIFY_DISCOURAGE_UPGRADABLE_NOPS |
                                                         SCRIPT_VERIFY_CLEANSTACK |
                                                         SCRIPT_VERIFY_CHECKLOCKTIMEVERIFY |
                                                         SCRIPT_VERIFY_CHECKSEQUENCEVERIFY |
                                                         SCRIPT_VERIFY_LOW_S

Standard script verification flags that standard transactions will comply with. However scripts violating these flags may still be present in valid blocks and we must accept those blocks.

Definition at line 35 of file policy.h.

Referenced by AcceptToMemoryPoolWorker(), MutateTxSign(), ProduceSignature(), and signrawtransaction().